Fluid control device



Fb., L M36., l H. W. LINK 2,@29941-@3 FLUID CONTROL DEVICE Filed April 20, 1934 Patented Feb. 4, 1936 f V2,029,493 FLUID CONTROL DEVICE Harry W. Link, Philadelphia, Pa., assignor, by

mesne assignments, to American Engineering Company, Philadelphia, Pa., a corporation of Pennsylvania Application April 20, 1934, Serial No. 721,540

2 Claims.

This invention relates to fluid control devices, and more particularly to the type of fluid control devices associated with pumps.

One object of the present invention is to provide a control for pumps which functions to maintain the associated pump on full stroke throughout a predetermined pressure range, to gradually reduce the discharge of the pump when the pressure exceeds a predetermined value, and to maintain a predetermined maximum pressure Aat substantially neutral stroke of the pump.

Another object is to provide in a control device of the stated character, adjustable flexible ImeanS, and a gauge associated therewith, whereby the predetermined pressure range may be readily varied.

Other and further objects will become apparent as the description of the invention progresses.

Of the drawing:

Fig. 1 is a side elevational View partly in section showing the general arrangement of the control system and the pump associated therewith.

Fig. 2 is a view taken substantially along line 2-2 of Fig. 1.

Fig. 3 is a sectional elevational view taken thro-ugh the control mechanism and showing the operating parts thereof in normal position.

Fig. 4 is a similar view of the control mechanism showing the parts in operated position.

Referring to the drawing, the numeral I indicates generally the iluid control device comprising the present invention, which as shown in Figs. 1 and 2, is secured to one of the side faces 2 of a pump 3 by bolts 4. Pump 3 may be of the general type shown and described in the United States patent to Hele-Shaw No. 1,077,979, or of any other suitable type. A pair of pipes 5 and 6 connect the pressure and suction sides respectively of pump I with the device to be operated thereby.

The control device I comprises a supporting bracket 1 having an upper threaded tubular portion 8 to which is secured an extended hollow cap member 9. The upper end of cap member 9 is provided with a tapped aperture I0 which receives a tubular plug II. The upper end of plug I I has secured thereto a hand wheel I2, the purpose of which will presently appear. As shown more particularly in Figs. 3 and 4, a fluid motor I3 having a piston I4 operating therein, is secured to the lower end of bracket 'I. A piston rod I5 secured to the upper end of piston I4 is provided with a lower rack portion I6, an intermediate enlarged portion I l, and an upper reduced portion I8. The enlarged portion I'I extends through and is guided in an aperture I9 provided in bracket 'I while the reduced portion I8 extends through and is guided in the central bore of plug II. Rack I6 meshes with a segmental gear 29 mounted upon a shaft 2| journaled in bearings 22, 22 provided in side members 23 and 24 of bracket l. segmental gear 20 meshes with a second substantially horizontal rack 25, the upper surface of which bears against 5 a guide plate 23. Rack 25 has secured thereto the outer ends of a pair of rods 2l and 28, the inner ends of which are secured to the sliding block 29 of pump 3. By this construction it is seen that when rod I5 is moved downwardly slid- 10 ing block 29 will be moved to he left thereby placing the pump 3 on stroke. The means for urging rod I5 downwardly will now be described in detail.

As shown in Figs. 3 and 4, a coil spring 30 exl5 tends between a pair ci spring seats 3l and 32 slidably mounted on the reduced portion I8 of rod I5. A flat disc 33 also slidably mounted on rod I5 is provided between the lower end of plug II and the upper reduced end 34 of spring seat 20 32. A ball bearing 35 surrounds the reduced portion 34 of spring seat 32, the upper race of which bears against disc 33 while the lower race engages an annular shoulder 36 on said spring seat.

, Spring seat 3I abuts against the upper end oi 2.5,

enlarged portion I'I of rod l5.

It is well known that unless pressure is exerted against the sliding block 29 of pump 3, it will assume a neutral position and no fluid will be delivered by they pump. Therefore, it is seen 30 that when spring 30 has been so adjusted as to exert no pressure upon sliding block 29, it will assume a neutral position and no fluid will be delivered by pump 3. To place pump 3 on stroke spring 3l! is placed under compression by adjust- 35 ment of hand wheel I2. The pressure exerted upon sliding block 29 is counteract-ed by fluid motor I3 which is connected to the pressure side of pump 3 by a pipe 3l. Thus, when the pressure developed by pump 3 exceeds the tension 40,

of spring 3i), piston I4 will move upwardly thereby actuating sliding block 29 toward neutral position through the connections just described. As piston I4 moves upwardly the tensin of spring 3 becomes progressively greater, and the sliding 45 block will be actuated to neutral position only when the maximum predetermined pressure in pump 3 is developed for that particular adjustment of spring 30. The maximum predetermined pressure required to place pump 3 on neutral 50 stroke may thus be maintained as long as desired. 'Ihe predetermined pressures may be varied by simply adjusting the tension of spring 30 the proper amount. inasmuch as the elective area of piston I4 remains constant, the spring 55 adjustments determine the pressures in the system.

Spring 30 may be so designed as to operate within a constant pressure range for each setting thereof. For example, at one setting the 60 square inch. Upon each increase in pressure from this value the discharge of the pump will gradually decrease until the developed pressure reaches 1,400 pounds per square inch, when the puni-p is adjusted to neutral stroke, and the pressure in the system is retained at this value. A spring so designed. it is seen, operates within the constant range ci pounds per square inch. It is obvious, however, that springs may be designed to operate within greater o-r lesser ranges of pressure as well, between maximum discharge and no discharge of the pump.

To facilitate adjustment of the spring 3B the proper amount, a gauge 38 calibrated in pounds per square inch oi pressure developed in pump 3 which the spring 30 is capable of withstanding at diierent adjustments thereof, is provided on the outer face of cap 9. The pointer 33 of this gauge is secured to spring seat 32 and projects outwardly therefrom through a vertical slot i0 provided in cap Si. A lock nut 4l having an operating arm i2 attached thereto is provided to lock plug in adjusted position.

The gauge may indicate both the predetermined pressure at which the discharge begins to decrease and the maximum pressure to be retained in the system for each spring adjustment, or either of said pressures.

A three-way valve 43 is placed in the pressure pipe 5 which is adapted in one position to permit the ilow of iiuid from pump 3 to the work and in another position to permit the flow of uid from the pump to flow to exhaust through a pipe 44.

Pump 3 is provided with a drive shaft 45 which may be connected to an electric motor or any other suitable driving means.

From the foregoing description, it is seen that to condition the control device for operation, the lock nut 4i is loosened to permit movement oi' plug ll. Hand wheel i2 is then operated to compress spring until the pointer 39 registers with the desired pressure indicated on gauge 38. Upon compression of spring 30 rack I6 is moved downwardly causing segmental gear 2S to rotate in a counter clockwise direction, which through its connection with rack 25 causes the latter, as Well as sliding block 29 of pump 3, to move to the left to full stroke position. Pump 3 will now discharge through pipe 5. When the pressure developed by pump 3 builds up to the predetermined amount determined by the adjustment of spring 30, piston I4 of fluid motor I3 will urge rack I6 upwardly against the tension of spring 30 thereby causing siidlng block 29 to move toward neutral position. This movement continues as the pressure of pump 3 increases until the maximum pressure for that adjustment of spring 3D is reached, when the sliding block 2S is adjusted to neutral position. This maximum pressure is maintained until the pressure decreases or until valve 43 is adjusted to divert the discharge of Dump 3 to exhaust. The work may then be removed, and the device is ready for another cycle of operation.

After spring 30 has been adjusted as aforesaid it is held in adjusted position by lock nut 4l.

While the embodiment herein described is admirably adapted to fulfill the objects primarily stated it is to be understood that it is not intended to limit the invention to the one embodiment shown since it may be embodied in other forms, all coming within the scope of the claims which follow.

What is claimed is:

1. In a device of the class described, the combination with a variabie stroke pump, of stroke adjusting means for said pump, a bracket secured to one side of said pump, having an open framework, a vertically disposed cylinder mounted at the lower end of said bracket having a piston operating therein, means connecting said cylinder to the pressure side or" said pump, a substantially tubular extensie-n provided at the upper end of said bracket, an extended cap secured to said extension, a vertically disposed rod slidably mounted in said bracket, and extending upwardly through said tubular portion and cap, said rod abutting the upper end oi said piston, a rack integral with the lower end of said rod, a seg mental gear journaled in said bracket meshing with said rack, a substantially horizontal rack secured to said stroke adjusting means also meshing with said segmental gear, a coil spring mounted in said tubular extension and cap, adapted to exert a downward pressure on said rod to move said stroke adjusting means toward on-stroke position, and means for adjusting the compression of said spring.

2. In a device of the class described, the combination with a variable stroke pump, of stroke adjusting means for said pump, a bracket secured to one side of said pump having an open framework, a vertically disposed cylinder mounted at the lower end of said bracket having a piston operating therein, means connecting said cylinder to the pressure side of said pump, a substantially tubular extension provided at the upper end of said bracket, an extended tubular cap secured to said extension, a vertically disposed rod slidably mounted in said bracket and extending upwardly through said tubular portion and cap, said rod abutting the upper end of said piston and having provided at the lower end thereof a rack, a gear journaled in said bracket meshing with said rack, a substantially horizontal rack secured to said stroke adjustinfT means, and also meshing with said gear, a coil spring mounted in said tubular extension and cap, a pair of spring seats for said coil spring, one of said seats engaging an enlarged portion of said rod whereby said spring is adapted to exert a downward pressure on said rod and piston to move vsaid stroke means toward on-stroke position, means for adjusting the other of said spring seats to vary the compression of said spring, a pointer secured to said adjustable spring seat and extending through a substantiallyvertieal slot prolvided in said cap, for indicating the compression of said spring, and means for locking said adjustable means in each position of adjustment.

HARRY W. LINK. 

